Oxytocin

Where it comes from

Made in

Large neurons of the hypothalamus, in the paraventricular and supraoptic nuclei

Sent out by

Carried down the neurons’ axons into the posterior pituitary and let into the blood by suckling, by the stretch of the cervix in labour, and by touch

Acts on

• Uterus (the myometrium)
• Breast (myoepithelial cells around the milk ducts)
• Brain (amygdala and reward circuits)

What it does

• Drives the contractions of labour
• Squeezes milk out of the ducts during a feed
• Shapes social recognition, trust and pair bonding

In medicine

• Synthetic oxytocin is given to start or strengthen labour and to stop bleeding after birth ²
• Carbetocin, a longer-acting analogue, is used after caesarean section outside the United States
• Intranasal oxytocin has been trialled in autism and anxiety without a consistent benefit ³

Beyond the body’s own use

• Intranasal oxytocin has been tested for social cognition in autism and for social anxiety; the largest trial, in 290 children and adolescents, found no benefit over placebo ³
• It is studied for the social symptoms of schizophrenia, for postpartum depression and for the appetite of Prader-Willi syndrome; none of these is an approved use
• Oxytocin is broken down in the gut, so a swallowed drop or capsule does not reach the blood